A 90% win rate can lose money if the 10% of losers are huge, and a 35% win rate can be very profitable if winners are large. Win rate only means something alongside risk-reward-ratio in the expectancy formula.
High-win-rate strategies (many mean-reversion and premium-selling approaches) feel good and blow up rarely but badly. Low-win-rate strategies (trend following) feel bad and bleed slowly with occasional big wins.
Example: strategy A wins 80% with +0.5R wins and -2R losses: expectancy = 0.4 - 0.4 = 0. Strategy B wins 35% with +3R wins and -1R losses: expectancy = 1.05 - 0.65 = +0.40R.
Related: expectancy, risk-reward-ratio, profit-factor, sample-size